1. Field of the Invention
The present invention relates to an insertion apparatus to be inserted into a cavity.
2. Description of the Related Art
In general, an insertion apparatus to be inserted into a cavity, such as an endoscope, comprises a flexible insertion section which is to be inserted into an examinee for observation and treatment of an affected portion of the examinee, and an operation section which is operated to bend the insertion section in a UD direction and an RL direction. The operation section is provided with a bending operation knob. When the affected portion is observed or treated, the bending portion at the distal end of the insertion section can be curved in a desired direction by operating the bending operation knob.
An outer tube, covering the bending portion of the insertion section of the endoscope, can be secured by means of a string or a shape memory alloy.